Safety trip device for motors responsive to temperature, speed, and pressure



May 11, 1951 E. G. EPPENS SAFETY TRIP DEVICE FOR MOTORS RESPONSIVE T0TEMPERATURE, SPEED, AND PRESSURE 2 Sheets-Sheet 1 Filed Nov. 19, 1948INVENTOR ERNEST G-EPPENS. BY

HIS A ORNEY.

May 11, 319511 E. e. EPPENS SAFETY TRIP DEVICE FOR MOTORS RESPONSIVE TOTEMPERATURE, SPEED, AND PRESSURE 2 Sheets-Sheet 2 Filed Nov. 19, 1948INVEN TOR ERNEST G. EPPENS. BY Z1! 1 HIS ATTORNEY.

Patented May I, 1951 SAFETY TRIP DEVICE FOR MOTORS RE- SPONSIVE TOTEMPERATURE, SPEED,

AND PRESSURE Ernest G. Eppens, Phillipsburg, N. J., assignor'toIngersoll-Rand Company, New York, N. Y., a. corporation of New JerseyApplication November 19, 1948, Serial No. 61,000

' This invention relates to safety devices for motors and moreparticularly to a device for shutting off a motor in the event itstemperature or speed becomes excessive or the oil pressure becomes toolow.

It is one object of this invention to combine the speed, temperature andoil pressure control devices into one simple compact unit.

It is a further object to provide a single control arm for starting,stopping and resetting the control device.

' Other objects will become apparent in the following specification andaccompanying drawings in which:

Figure 1 is a side view, partly in section, of a control deviceconstructed in accordance with the practice of the invention,

' Fig. 2 is a top view of Figure 1,

Fig. 3 is an end view of Figure 1,

Fig. 4 is a transverse view taken through a detail of Figure 1 along theline 4-4 looking in the direction of the arrows, and

Fig. 5 is a transverse view through a detail of Figure 1 taken along theline 5-5 looking in the direction of the arrows.

Referring to the drawing and more particularly to Figure 1, a preferredform of the safety mechanism is shown adapted to a motor, a portion ofthe casing I of which is shown. The safety mechanism comprises, ingeneral, devices ll, [2 and I3 responsive, respectively, to abnormalconditions of speed, temperature or oil pressure of the motor to actuatea lever [4 thereby releasing a control rod which effects the shuttingdown of the motor by actuating a device 22 of any conventional form,depending on the type of motor to which the safety mechanism is adapted,for stopping the motor. A control handle I6 is provided to reset thecontrol rod [5 after it has been released by one of the control devicesand it also serves as a manually operated means for releasin the controlrod 15 for stopping the motor.

More specifically, the safety device includes a plate I l secured to thecasing [0 by bolts I8 and on which the various automatic control devicesare mounted. In furtherance to this end, a support member i9 projectsfrom the plate I! and slidably encircles the end portion of the controlrod l5 disposed to rotate a lever 20, keyed to a shaft 2|, by which themotor shut down device 22 is actuated. For the sake of illustration,

this device is shown as being a fuel valve, the' 4 Claims. (Cl. 601)right (Fig. 1) or rearwardly direction effects clockwise rotation (asviewed in Fig. 1) of the shaft 2| to close the fuel valve 22. Theopposite or forward end of the control rod I5 is supported by a screw 24threaded in the plate I! and having a transverse hole 25 through whichthe rod l5 slidably extends. The body portion of the screw 24 serves asan axis or pivot for the hub 26 of the lever l4. Rotation of the lever[4 in a clockwise direction, as viewed in Fig. 1, effects engagement ofan abutment 21 on the lower edge of the lever I4 with a shoulder 28 onthe rod l5 to retain the rod l5 in its forward position wherein theoperation of the fuel valve is independent of the safety device.

On the rearward end of the lever 14 is a cam 29 having an inclinedsurface 30 which cooperates with the complementary inclined surface 3|on the control handle l6, rotatably mounted on a pin I threaded in theplate [1, in such a manner that when the handle [6 is rotated to itsrearward limiting position, the lever I4 is forced upwardly orcounterclockwise to release the control rod l5.

Slidablymounted on the housing [0 below the cam 29 and in line therewithis a pin 32 which cooperates with the speed control device H to lift orrock the lever and release the control rod l5 whenever the speed of themotor becomes excessive. To this end, an over speed device II isprovided to actuate the pin 32 and, in this instance, comprises anannular plate 33 keyed to a countershaft 34 on which is pivotallymounted a weight 35. The Weight 35 is mounted ofi center so that ittends, due to centrifugal force, to swingoutwardly against the force ofa spring 36 to strike the lower end of the pin 32 whenever the motorspeed exceeds a predetermined value. Interposed between the end of thepin 32 and the counterweight 35 is a lever 31 to transmit the movementof the counterweight 35 to the pin 32. A set screw 38 engaging theopposite end of the lever 31 serves to regulate the space betweenj' thecounterweight 35 and the end of the lever 31 which it strikes, therebyeffectively regulating the maximum speed of the motor. The speed atwhich the counterweight 35 moves out suificiently to strike the lever 31and move the pin 32 to release the control rod I5 is, of course,dependent on the strength of the spring 36 and the setting of the screw38.

' Disposed on the opposite or forward end of The forward' end 42 of therod I5 bears in the other cup 40. As is best seen in Figure 1, the pin39 is somewhat out of line, in this instance slightly above, withrespect to the forward end 42 of the rod I5-- thus, the spring 4| servesas a means for urging the controlrod I5 into its rearward position toeffect the closure of the fuel valve and also, due to the previouslymentioned misalignment, serves to urge the lever I4 into engagement withthe control rod to prevent said rearward movement of the rod I5.

Extending vertically upward from the lever I4 and integral therewith isa projection or arm 46 which is actuated by the temperature responsivedevice I2 for rocking the control lever I4 to re lease the rod I5. Infurtherance to this end, the device I2 includes a casing 43 for areciprocative plunger 44, the stem 45 of which bears against the freeend of the arm 46 which it actuates. Movement of the plunger 44 torelease the rod I5 is effected by the thermal expansion of a fluid in abulb or ball 41 positioned at a point in the motor casing I where it isdesired to keep the temperature below a predetermined maximum andcommunicating with the plunger chamber 48 through a conduit I46. Inorder to obviate the need for a tight fit between the plunger 44 and thecasing 43 and between the stem 45 and the casing 43, a Sylphon 49 isattached to the forward end of the casing and secured at the other endto the forward surface of the plunger 44 thereby preventing any leakageof fluid from the casing 43 along the stem 45. A spring 50 encirclingthe stem 45 within the sylphon 49 biases the plunger 44 towards itsnormal rearward position.

On the side of the arm 46 opposite the stem 45 and mounted on theprojection integral with the plate I! is the oil pressure responsivedevice I3 comprising a cylinder for the spring pressed piston 53 exposedon one side to the oil pressure of the motor through a conduit 54. Onthe opposite or rearwardly side of the piston 53 is a stem 55 extendingbeyond the rearward edge of the arm 46 and having a transverse pin 56 inits end to engage the arm 46. With this arrangement, whenever the oilpressure within the motor drops below a predetermined value, the spring51 will force the piston 53 forwardly or to the left, as viewed inFigure 1, and the pin 56 will rock the arm 46 of the lever I4 to releasethe control rod I5.

In order to prevent the pressure control I3 from releasing the controlrod I5 before the oil pressure of the motor builds up, when starting themachine, a bell crank 58 pivotally mounted on a pin 59 supported by abracket 66 of plate I1 is provided which at one end engages the pin 56and the other end is in alignment with the control handle I6 so thatwhen the handle I6 is in its forward limiting position, an abutment 6|on the handl I6 contacts the lever 58 to hold the piston 53 in arearward position against the pressure of biasing spring 51 therebypreventing the oil pressure device I3 from shutting off the motor beforethe oil pressure has increased sufficiently to overcome the spring 51.

The control handle I 6, as previously mentioned, serves to reset thecontrol rod I5 and to this end is provided with a pin 62 which lies inthe path of the shoulder 28 so that movement of the control handle I6 tothe left (Fig. 1) brings the rod I5 into a position to be engaged by theabutment 21. At this point, the pin 62 is retracted from the path of theshoulder 28 by the action of a shoulder 63, on the pin 62, which rideson a cam 64 4 mounted on the plate I1. A spring 65 interposed betweenthe shoulder 63 and the handle I6 assures continuous contact between theshoulder 63 and the cam 64. Thus, the lever I4 may be advanced furtherto bring the abutment 6| into contact with the bell crank 58 in themanner previously described, to hold the piston I5 in its rearwardposition. This cam arrangement serves, further, due to frictionalresistance to movement between the cam 64 and the shoulder 63, to retainthe control handle I6 in any position that it is set by the operator.

Briefly reviewing the operation of the control device, in order to startthe motor, the control handle I5 is rotated into its forward limitingposition thereby moving the control rod I5 into a position wherein it isengaged by the shoulder 21 and restrained from reverse longitudinalmovement, and the oil pressure device I3 is restrained from tripping thecontrol rod I5 until such time as the motor oil pressure builds up toits operating value. At this time, the handle I6 is rotated in thereverse or clockwise direction thereby releasing the oil pressure deviceI3 to operate in accordance with the motor oil pressure, and the rod I5is free to move in a rearward direction to shut down the motor wheneverit is released by the lever I4. As long as the rod I5 is retained in itsforward position by the shoulder 21, the fuel valve 22 is free to beactuated in accordance with the speed of the motor or any other controldevice (not shown) to which it may be operatively connected. Upon anyabnormal condition of pressure, temperature, or speed, the lever I4 isrocked in a counterclockwise direction, as viewed in Figure 1, by theappropriate control device to release the rod I5, which under theinfluence of the spring 4! overpowers any speed regulating device (notshown) to which the fuel valve 22, or other motor shut down device, maybe connected to shut oil the motor. The strength of the spring 4| isalso sufficient to rotate. the lever I4 in the event it is inadvertentlyleft in a position wherein the pin 62 is in line with the shoulder 21.In the event that it is desirable to halt manually the operation of themotor, it is merely necessary to move the lever I4 into its rearwardlimiting position thereby rocking the lever I4 to release the rod I5 ina manner described in detail hereinbefore.

It is now obvious to those skilled in the art that a safety deviceconstructed in accordance with the practice of the invention attains,among others, the objects hereinbefore stated and provides a relativelysimple yet highly compact device which is responsive to a plurality ofoperating characteristics of a motor to shut down the motor in the eventof an abnormal or dangerous condition in the motor which effects any oneof these characteristics and, further, any or all of these devices maybe reset by the simple expedient of rotating a single lever.

While I have shown and described a specific form of my invention, it isto be understood that various changes and modifications may be madewithout departing from the spirit of the invention as set forth in theappended claims.

I claim:

1. In a safety mechanism for motors, a valve for controlling the flow offuel to the motor, a rod movable longitudinally'to close said valve, alever engaging said rod against such longitudinal movement, means urgingsaid rod into position for actuating said valve to stop the motor andurging said lever into engagement of said rod,

a device responsive to the motor temperature for actuating said lever torelease said rod, a device acting responsively to the oil pressure ofthe motor to actuate said lever to release said rod, a device actingresponsively to the speed of the motor to actuate said rod, and acontrol handle acting upon movement in one direction to reset said rodand acting in the other direction to efiect the release of said rod.

2. In a safety mechanism for motors, a valve for controlling the flow ofmotive fluid to the motor, a rod movable longitudinally to actuate thevalve to shut ofi the motor, a pivot, a lever rotatably mounted on thepivot for engaging the rod to prevent longitudinal movement thereof,means for urging the rod to move longitudinally and for rotating thelever into engagement With said rod, an arm on the lever, and aplurality of devices acting in response to abnormal conditions ofvarious operating characteristics of the motor for engaging said arm torotate the lever out of engagement with the rod.

3. In a safety mechanism for motors, a valve for controlling the flow ofmotive fluid to the motor, a rod movable longitudinally to actuate thevalve to shut off the motor, a pivot, a lever rotatably mounted on thepivot for engaging the rod against longitudinal movement, means forurging the rod to move longitudinally and for rotating the lever intoengagement with said rod, an arm on the lever, a plurality of devicesacting in response to abnormal operating characteristics of the motorfor engaging said arm to rotate the lever out of engagement with therod, and a handle to reset the rod upon movement in one direction andfor disengaging the lever from the rod upon movement in the oppositedirection.

4. In a safety mechanism for motors, a valve for controlling the flow ofmotive fluid to the motor, a rod movable longitudinally to actuate thevalve to shut off the motor, a collar on the rod, a pivot, a leverrotatably mounted on the pivot having a shoulder for engagement with thecollar on the rod to prevent longitudinal movement of the rod, a springfor urging the longitudinal movement of the rod and for rotating thelever into engagement with the rod, a plurality of arms on the lever, aplurality of devices acting in response to abnormal operatingcharacteristics of the motor for engaging the lever arms to rotate thelever out of engagement with the rod, and a handle adapted to engage thecollar on the rod to reset the rod upon movement in one direction andadapted to engage an arm on the lever to disengage the lever from therod upon movement in the opposite direction.

ERNEST G. EPPENS.

REFERENCE S CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,989,230 Everett Jan. 29, 19352,201,123 Davis May 14, 1940 2,225,234 Schettler Dec. 17, 1940 2,423,728Ray July 8, 1947

